Poor vector competence of fleas and the evolution of hypervirulence in Yersinia pestis
Poor vector competence of fleas and the evolution of hypervirulence in Yersinia pestis
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DOI：
10.1086/429931
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发表时间：
2005-06-01
影响因子：
6.4
通讯作者：
Hinnebusch, BJ
中科院分区：
文献类型：
--
作者：
Lorange, EA;Race, BL;Hinnebusch, BJ
对致病性耶尔森氏菌属的群体遗传学和比较基因组学分析表明，节肢动物传播是鼠疫耶尔森氏菌（鼠疫病原体）在进化上近期才出现的一种适应性。我们发现，鼠疫耶尔森氏菌对其最熟练的传播媒介——印鼠客蚤的感染性以及随后的传播效率都很低。蚤类较差的媒介能力可能施加了选择压力，有利于高毒力鼠疫耶尔森氏菌克隆的出现和持续维持。特别是，作为鼠疫典型特征的快速致命的革兰氏阴性菌败血症是为了完成传播周期必须达到的高菌血症阈值水平的结果。流行病学建模预测，为了弥补哺乳动物宿主对节肢动物媒介相对较短的感染期，即使易感宿主种群密度很高，鼠疫流行也需要每个宿主有较高的蚤类负荷。
Population genetics and comparative genomics analyses of the pathogenic Yersinia species have indicated that arthropodborne transmission is an evolutionarily recent adaptation in Yersinia pestis, the agent of plague. We show that the infectivity of Y. pestis to its most proficient vector, the rat flea Xenopsylla cheopis, and subsequent transmission efficiency are both low. The poor vector competence of fleas likely imposed selective pressure that favored the emergence and continued maintenance of a hypervirulent Y. pestis clone. In particular, the rapidly fatal gram-negative sepsis that typifies plague is a consequence of the high threshold bacteremia level that must be attained to complete the transmission cycle. Epidemiological modeling predicts that, to compensate for a relatively short period of infectivity of the mammalian host for the arthropod vector, plague epizootics require a high flea burden per host, even when the susceptible host population density is high.